Just when we thought Day 2 of Build would all be about servers and cloud services, Microsoft CEO Steve Ballmer took the stage at this morning's keynote. First order of business? Congratulating the Windows 8 team on achieving 500,000 downloads of the Windows 8 Developer Preview overnight. Speaking of previews, Ballmer also took the time to address early impressions of the operating system, saying "We still have a long way to go with Windows 8." Ballmer didn't have any major announcements for us, as he apparently just happened to be in town for an analyst briefing. Still, that didn't stop him from leaving the stage with a strong, "developers, developers, developers!" More pics of the brief appearance below.